Liquid Supply Apparatus with Accumulator Pressure Stabilization

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Solution Overview

Problem

Existing inkjet technologies struggle to stably convey and discharge high-viscosity inks over distances due to issues such as ink separation, precipitation, nozzle clogging, and fluctuating pressure, particularly in configurations that rely on hydraulic head pressure or airless spray methods.

Innovation Solution

A liquid supply apparatus incorporating an accumulator and a circulation path that stabilizes pressure and flow rate fluctuations by using a diaphragm pump, filter, and pressure control devices to maintain a consistent flow-through mechanism, including a configuration with multiple pressurizing tanks and regulators to manage pressure differentials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If hydraulic head pressure is used to convey high-viscosity ink through circulation, then the structure is simple, but the ink cannot be conveyed stably and nozzle clogging occurs

Engineering Contradiction:
Improvecirculation structureVSAvoidink conveyance stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The ink is pressurized in advance in a pressurizing tank before entering the circulation system. This preliminary pressurization ensures that high-viscosity ink can overcome resistance and flow smoothly through the discharge head, preventing clogging and maintaining stable conveyance throughout the circulation process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A pump is introduced as an intermediary device between the pressurizing tank and the discharge head to actively propel the high-viscosity ink through the circulation path. This intermediary mechanism overcomes the insufficient pressure of simple hydraulic head pressure, ensuring reliable ink flow without requiring complex circulation structures.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of moving object

If airless spray is used to discharge high-viscosity ink over distance, then discharge distance is improved, but ink separation and precipitation occur

Engineering Contradiction:
Improvedischarge distanceVSAvoidink composition stability
Core Design Contradiction:
Length of moving objectVSStability of the object's composition

Solution Approach 1:

The ink is pre-pressurized and continuously circulated through the discharge head before discharge. This preliminary circulation prevents solid components from settling and precipitating, maintaining homogeneous ink composition even when discharged over long distances using airless spray technology.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system maintains continuous circulation of high-viscosity ink through the discharge head, ensuring that the ink remains in constant motion and does not stagnate. This continuous action prevents separation and precipitation of solid components, maintaining ink stability during long-distance discharge operations.

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If differential pressure is provided between filling tank and drain tank, then flow-through is achieved, but pressure fluctuations cause discharge instability

Engineering Contradiction:
Improveflow-through achievementVSAvoiddischarge consistency
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The ink is pressurized in advance in a dedicated pressurizing tank before entering the discharge head. This preliminary pressurization provides stable and sufficient pressure for consistent discharge, eliminating the pressure fluctuations that occur when relying solely on differential pressure between filling and drain tanks.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A pump is introduced as an intermediary to actively control and stabilize the pressure of high-viscosity ink during circulation. This intermediary mechanism compensates for pressure fluctuations, ensuring consistent discharge even when differential pressure varies between the filling and drain tanks.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Speed

If high pressure is applied for airless spray, then discharge velocity is improved, but ink separation and precipitation advance

Engineering Contradiction:
Improvedischarge velocityVSAvoidink homogeneity
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The ink is pre-pressurized and continuously circulated through the discharge head before high-velocity discharge. This preliminary circulation keeps solid components suspended and prevents precipitation, allowing high-pressure airless spray to achieve high discharge velocity without causing ink separation or loss of homogeneity.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution enables stable discharge of high-viscosity inks over distances by mitigating pressure and flow rate fluctuations, preventing nozzle clogging and ensuring consistent ink application.

Implementation Method 1

an accumulator installed on the ink flow path at a position downstream from the pressurizing tank and upstream from the discharge head, which absorbs the fluctuation in the pressure of the ink flowing through the ink flow path

Methodology Applied
Scientific EffectPressure fluctuation absorption: Accumulator (energy)

Implementation Method 2

a pump installed on the ink flow path at a position downstream from the pressurizing tank... which conveys the ink flowing through the ink flow path

Methodology Applied
Scientific EffectPressure feeding: Pump

Data Source

PatentEP4393715B1Liquid supply apparatus and liquid application apparatus
Publication Date: 2025.07.09 RICOH CO LTD
  • EP4393715B1 patent drawingFigure 1
  • EP4393715B1 patent drawingFigure 2A~3B
  • EP4393715B1 patent drawingFigure 4A~4B

AI summary

A liquid supply apparatus (100) includes a compressed air supply source (200), a pressurizing tank (101, 102), a feeder (121), a discharge head (123), a mitigation device (131, 131-2, 131-3), and a circulation path. The discharge head (123) has a nozzle to discharge liquid from an internal flow path. The mitigation device (131, 131-2, 131-3) is installed on a liquid flow path (203, 204, 205) at a position downstream from the pressurizing tank (101, 102) and upstream from the discharge head (123). The mitigation device (131, 131-2, 131-3) absorbs a fluctuation in pressure of the liquid flowing through the liquid flow path (203, 204, 205). In the circulation path, the feeder circulates the liquid in the liquid flow path (203, 204, 205) in an order of the pressurizing tank (101, 102), the mitigation device, the discharge head (123), and the pressurizing tank (101, 102).